1.1 Field of the Invention
The present invention relates to Workflow Management System or a computer system with comparable functionality (WFMS). More particularly the invention relates to a method and means for processing of compensation scopes in a process model in the particular instance that the compensation scopes are comprised within atomic scopes.
1.2 Description and Disadvantages of Prior Art
A new area of technology with increasing importance is the domain of Workflow-Management-Systems (WFMS). WFMS support the modeling and execution of business processes. Business processes executed within a WFMS environment control who will perform which piece of work of a network of pieces of work and which resources are exploited for this work. The individual pieces of work might be distributed across a multitude of different computer systems connected by some type of network.
IBM WebSphere Business Process Choreographer represents such a typical modern, sophisticated, and powerful workflow management system. It supports the modeling of business processes as a network of activities. This network of activities, the process model, is constructed as a directed, acyclic, weighted, colored graph. The nodes of the graph represent the activities, which define the individual tasks that need to be carried out. In general, each of the activities is associated with a piece of code that implements the appropriate task. The edges of the graph, the control connectors, describe the potential sequence of execution of the activities. Definition of the process graph is via a graphical editor or a flow definition language, such as Business Process Execution Language for Web Services (BPELWS).
Advanced WFMSs support the notion of scopes, also named spheres. A scope provides the capability to assign a set of properties or handlers to a set of activities. In particular, scopes are used to specify transaction boundaries:                an atomic scope indicates that the enclosed activities are carried out as an atomic transaction;        a compensation scope indicates that the enclosed activities are part of a long running transaction. In addition to the enclosed activities compensation scopes allow to define so-called compensation activities which are executed after abnormal termination of a compensation scope to compensate, i.e. to undo, the effects of the execution of the activities within the compensation scope prior to the abnormal termination.        
If a compensation scope is embedded within an atomic scope, the combined rollback and restart processing may cause certain anomalies.
1.3 Objective of the Invention
Therefore a need exists in prior art to avoid these anomalies by introducing an alternate and improved rollback handling of a compensation scope comprised within an atomic scope.